I have a used water pump off of an '05 parts truck. It has the steel impeller, spins freely and smoothly with no end play. First question is would I be foolish to reuse this pump and second would tigging the gear and impeller be advised. TIA
Considering it is less then a hundred bucks for a new one and how much of a PITA it is to change, I would put a new one in personally. As far as Tig or Mig welding it, opinions vary I have had good luck simply drilling and migging them in the past, just be careful on the block side as theres not much clearance there and a fat weld bead will rub.
Get a new one. The seals go bad eventually. Just did mine this year from leaking out of the weep hole. 150,000 miles. Got a new AC Delco on Amazon for $68
Pinned is more reliable. But for most welded is fine. You can drill a hole down the shaft like a makeshift keyway and fill that with weld as well as all the way around.
And yes, just get a new one. If you have access to a welder then just get a Delco pump. If not get a pinned danville.